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In the presence of visible-light photoredox and chiral phosphate catalysts, a novel asymmetric Friedel-Crafts reaction of indoles and readily accessible α-amino acid derived redox-active esters is established to afford enantioenriched 1-indolyl-1-alkylamine derivatives in moderate to high yields and with high levels of enantioselectivities. This method not only shows a mild and efficient alternative for the in situ generation of N-acyl imines but also indicates the feasibility of a multicatalyst system for asymmetric photoredox catalysis.
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http://dx.doi.org/10.1021/acs.orglett.9b00442 | DOI Listing |
Org Lett
September 2025
Department of Chemistry, University of Helsinki, 00014 Helsinki, Finland.
Visible-light-excited 3,6-bis(trifluoromethyl)-9,10-phenanthrenequinone (PQ-CF*) was used as a photocatalyst in the synthesis of 3-substituted -pyridyl indoles via cyclization of 2-vinylarylamines, where the photocatalyst was catalytically regenerated with the chloro(pyridine)cobaloxime complex. The versatility of the reaction was shown with 22 substrates providing up to 83% yields. Based on the mechanistic studies, we propose that PQ-CF directly activates the N-H bond, generating a nitrogen-centered aminyl radical as the key intermediate.
View Article and Find Full Text PDFOrg Lett
September 2025
Zhejiang Key Laboratory of Green Manufacturing Technology for Chemical Drugs, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
Herein, we report an efficient visible-light-mediated reaction of alkynones with ethyl diazoacetate for the construction of cyclic frameworks containing the 1,4-dicarbonyl moiety. In this photocatalytic system, a readily available phenothiazine derivative serves as the organic catalyst, which, upon photoexcitation, gains strong reducing power to facilitate the divergent synthesis of structurally diverse thioflavone derivatives. This metal-free protocol exhibits broad substrate scope and mild reaction conditions, providing a versatile and sustainable approach to high-value heterocycles.
View Article and Find Full Text PDFSoft Matter
September 2025
Transport phenomena, Chemical engineering Department, Faculty of applied sciences, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands.
Polymer membranes are prime candidates for separation and purification processes, with their functionality enhanced by nanoparticle incorporation and diverse polymer structures. Poly(ionic liquids) (PILs), highly charged electrolyte-like polymers, are gaining interest as membrane polymer matrices. Embedding photocatalytic nanoparticles enables water purification through filtration and degradation reactions.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Back electron transfer (BET) is a critical process that will impair singlet photoredox catalysis. In this study, we present that the S1 excited state of a photocatalyst with intramolecular charge transfer (ICT) character can effectively inhibit BET, due to the spatial separation of the electronic couplings of the forward and back electron transfer pathways. With phenoxazine-modified molecules as photocatalysts and chlorobenzene as the substrate, we analyze how the spatial distribution of electronic couplings with/without ICT states would affect the photocatalysis efficiency.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2025
State Key Laboratory of Low Carbon Catalysis and Carbon Dioxide Utilization, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou, 730000, China.
Allylic alcohols are versatile and essential building blocks in synthetic chemistry, widely used for the preparation of complex molecules, pharmaceuticals, and materials. We report here a regiodivergent reductive hydroxymethylation of terminal alkynes with aqueous formaldehyde to prepare allylic alcohols enabled by visible light photoredox and cobalt dual catalysis. Using readily available, bulk, and cheap aqueous formaldehyde as a simple C1 source, this method allows for the selective production of both linear and branched allylic alcohols in one-step manner.
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